Orthodontic bands serve an important function during the orthodontic treating of a patient to correct malocclusions. Such bands may be applied to all of the teeth or only to anchor teeth in accordance with the particular technique preferred by the orthodontist. Importantly, the bands reduce tendencies for carious attack on the tooth due to their circumferential protection of the enamel. Additionally, they are important in that they allow secure attachment of various brackets or tubes to the teeth that facilitate orthodontic biomechanics. Finally, the bands serve to more evenly distribute a tooth-moving force over the area of an individual tooth.
The use of orthodontic bands has always been common to the profession of orthodontics either through manual "pinching" of bands or the more modern seamless ring-shaped bands. Another historic problem has been associated with their benefits in that the cement or adhesive seal between the inner band surface and the luting medium tends to loosen and allow dislodging of the band. Loose bands may occur from many different situations such as because of occlusal forces, extraoral tractive forces, masticatory forces from food bolus, or even improper sizing and seating. Additionally, luting agents may be mixed improperly or moisture may be introduced into the agents prior to complete cement setup.
Clinically, loosened bands can lead to micro-leakage of electrolytes or other contaminants which often cannot be detected through the normal course of orthodontic treatment. Upon removal of a loose band at the end of treatment, it may then be discovered that deleterious effects of cement seal failure have caused decalcification or carious attack of the tooth surface. Other clinical problems resulting from loose bands include the frustration of emergency office visits and the scheduling of extra appointments to clean the tooth and re-cement another band for the continuance of orthodontic treatment. Additionally, there may be a relapse of desired tooth movement prior to the replacement of a loose or dislodged band.
Heretofore, it has been known to apply metal mesh to at least parts of the inner surfaces of bands to increase tension. While some increased tension is obtained, the mesh takes up room by increasing the thickness of the band at the area of mesh attachment. Further, an extra step in manufacturing of the band is required in applying the mesh after the band has been completely formed. That the mesh takes up room affects the fit of the band on the tooth in an adverse manner.
It has also been proposed to sandblast the inner surface of bands to increase the luting agent strength between the band and the cement. This method of texturizing the inner surface is undesirable because it becomes a costly secondary operation following band manufacture.
It has also been proposed to acid-etch the band material prior to formation of the band so that the retention can be increased. This method produces a minimal texture and can be lost in further manufacturing steps because of close tool/material tolerances. Further, increased tool wear and replacement costs become burdensome.
Machined or engraved physical grooves could be employed on the stainless steel foil prior to band manufacture. Because foil thickness is usually 0.005 to 0.007 inch, and therefore generally about 0.006 inch thick, depth tolerance problems become critical and tear or tensile weakness in the foil becomes a problem when the band is completed.
It has also been known to photoetch blind holes into the base member of an orthodontic bracket which is thereafter sandblasted for roughening purposes to give the best holding strength, as disclosed in U.S. Pat. No. 4,243,386. It has also been known to texture the tooth-attaching sides of brackets in other ways in order to increase retention with a bonding adhesive.